Different types of foundation systems have been developed so as to support offshore wind energy convertors, such as gravity base foundations, whose on-bottom stability is simply due to their own weight on the seabed; monopile type foundations, in which a steel column is embedded several meters into the seabed, tripod-type foundations comprising one column and at least three support legs embedded into the seabed, and jacket type foundations, which are steel towers made of braced members.
These structures are fitted to support wind energy convertors in moderately deep waters, for water depth greater than approximately 40 meters. However, the size of these structures significantly increases with the water depth, and so does the cost of fabrication, transport, and installation since these structures have to be massive and strong enough to resist forces generated by current, waves, and wind.
Floating platforms are well known for the installation of wind turbines in deeper water depth, which comprise one or several columns submerged by about 100 meters but not resting on the seabed. These floating platforms are expensive and typically require water depth beyond 200 meters.
The present invention provides a foundation support system for an offshore wind energy convertor, and is designed to have a low cost and good resistance to the forces generated by current, waves, and wind.
In this regard, the invention is characterized by the fact that the column and foundation base are linked by an articulated joint connection, i.e., any type of connection that allows the column to tilt with respect to the foundation base in any direction from a vertical axis.
Depending on the method of construction, the system may present one or several of the following features, separately or following all possible technical combinations:                the system comprises mooring lines, equipped with dead weight, linking the column to the seabed;        the column comprises in its upper part at least one tight, internal compartment;        the column comprises in its upper part at least two independent tight, internal compartments;        at least one internal compartment may be partially emerging when the column axis is nearly vertical;        the column comprises in its upper part, near the sea surface, a cross section larger than in its lower part;        the system comprises at least one buoyancy caisson, fixed to the column;        the foundation base is equipped with at least one buoyancy caisson, which can be ballasted;        the column comprises a steel lattice structure;        the column comprises at its top a recess suited to house the lower part of the wind energy convertor, and allows the wind energy convertor to slide inside the column; and        the column is connected to the base through an articulated joint.        
The present invention also provides a complete wind power generator facility, which comprises a wind power generator unit and the foundation support system.
The present invention also provides a process of fabrication, transport, and installation of a wind energy convertor facility, which comprises the following stages:                construction of a wind energy convertor and a foundation system to support it, the system comprising a foundation base resting on the seabed and a column supporting the wind energy convertor, the column and the foundation base being linked by a articulated joint connection that allows for tilting motions of the column with respect to the foundation base in any direction with respect to a vertical axis;        transport of the foundation support system to a wind farm location;        lowering the foundation support system down to the seabed by ballasting the foundation support system;        installing the wind energy convertor onto the foundation support system after the foundation system is lowered down to the seabed, using a crane vessel moored to the foundation system.        